HDU 1051 Wooden Sticks（贪心）

HDU 1051 Wooden Sticks（贪心）

Wooden Sticks

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 17320    Accepted Submission(s): 7056

Problem Description

There is a pile of n wooden sticks. The length and weight of each stick are known in advance. The sticks are to be processed by a woodworking machine in one by one fashion. It needs some time, called setup time, for the machine to prepare processing a stick. The setup times are associated with cleaning operations and changing tools and shapes in the machine. The setup times of the woodworking machine are given as follows: (a) The setup time for the first wooden stick is 1 minute. (b) Right after processing a stick of length l and weight w , the machine will need no setup time for a stick of length l' and weight w' if l<=l' and w<=w'. Otherwise, it will need 1 minute for setup. You are to find the minimum setup time to process a given pile of n wooden sticks. For example, if you have five sticks whose pairs of length and weight are (4,9), (5,2), (2,1), (3,5), and (1,4), then the minimum setup time should be 2 minutes since there is a sequence of pairs (1,4), (3,5), (4,9), (2,1), (5,2).

Input

The input consists of T test cases. The number of test cases (T) is given in the first line of the input file. Each test case consists of two lines: The first line has an integer n , 1<=n<=5000, that represents the number of wooden sticks in the test case, and the second line contains n 2 positive integers l1, w1, l2, w2, ..., ln, wn, each of magnitude at most 10000 , where li and wi are the length and weight of the i th wooden stick, respectively. The 2n integers are delimited by one or more spaces.

Output

The output should contain the minimum setup time in minutes, one per line.

Sample Input

3 5 4 9 5 2 2 1 3 5 1 4 3 2 2 1 1 2 2 3 1 3 2 2 3 1

Sample Output

2 1 3

题意：1，第一根木棍设置时间是1min，

2，之后处理的木棍的长度为l，权重为w，如果l1<=l，w1<=w,就不用设置时间，否则就要1min的设置时间。

求最小设置时间

题解：贪心，先根据l从小到大排序，注意，当l相同时，再根据w从小到大排序。

AC代码：

#include#include#include#include#include#include#include#include#includetypedef long long LL;using namespace std;struct ac{ int l,w; int flag;}node[5005];int cmp(ac a,ac b){ return a.l>t){ while(t--){ count=0; for( i=0;i<5005;i++) node[i].flag=0; cin>>n; for(i=0;i>node[i].l; cin>>node[i].w; } sort(node,node+n,cmp); for(i=0;i=node[k].l&&node[j].w>=node[k].w&&node[j].flag==0) { node[j].flag=1; k=j; } } } printf("%d\n",count); } } return 0;}

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